Heat treating apparatus for woven fabrics



' P 51 B. YB,.PURDY ETAL 3,343,274

HEAT TREATING APPARATUS FOR WOVEN FABRICS Filed Jan. 27, 1965 s Sheets-Sheet 1 7 INVENTORS Y I sauce 8.PURDY ADRIAN IZGODSCHALX AT TORNEY Sept. 26, 1967 B. B. PURDY ETAL v 3,343,274

HEAT TREATING APPARATUS FOR WOVEN FABRICS 3 Sheets-Sheet 2 Filed Jan.

INVE NTORS BRUCE B. PURDY ADRIAN T- GODSCHALX HEAT TREATING APPARATUS FOR WOVEN FABRICS Filed-Jan. 27, 1965 5 Sh eetsSheet s n i 17/ E: 27 IN INVENTORS BRUCE B. PURDY ADRIAN T. GODSCHALX ATTORNEY United States Patent C) 3,343,274 HEAT TREATING APPARATUS FOR WOVEN FABRICS Bruce B. Purdy, Freedom Township, Outagamie County, and Adrian T. Godschalx, Appleton, Wis., assignors to Appleton Wire Works Corp., Appleton, Wis., 21 corporation of Wisconsin Filed Jan. 27, 1965, Ser. No. 428,329 2 Claims. (Cl. 34-68) This invention relates to apparatus for heat treating woven synthetic fabrics and more specifically it resides in an apparatus that includes a radiant heat source for placement in close proximity to an area of fabric together with smoothing rolls bearing against the fabric along the margins of the area subject to the radiant heat.

Large fabrics woven from synthetic materials with an open mesh are finding increasing use in a variety of applications. One such application consists of papermaking fabrics in both the wet and dry ends of papermaking machines. These fabrics are typically woven from nylon, and other synthetic materials such as Dacron, Orlon and Dynel may be suitable. in open mesh fabrics for a variety of additional applications. To function properly these fabrics must usually be treated to retain dimensional stability, and such treatment takes the form of heat treating under tension at temperatures elevated above those of intended use. A papermaking application is typical of the problem involved. A papermaking fabric may be over 200 inches wide and 200 feet or more in length, and the nylon from which it may be woven may have a mesh of approximately 14 to 120 warp threads to the inch and an open area of about 25% of the total area. When in use on a papermaking machine such fabric is subject to lengthwise tension involving very substantial forces, which may readily cause a dimensional change in the fabric if the material from which it is made readily stretches, thereby making the fabric useless for papermaking. Synthetic materials normally stretch considerably under tension, and hence they will be unsuited for papermaking unless some procedure is undertaken to dimensionally stabilize them before use.

Open mesh fabrics are particularly subject to dimensional change, since they do not have fill to give them dimensional stability, and the threads can migrate toward one another to make a more compact fabric. Consequently, it has been customary to stabilize these fabrics by heat treatment, before use, by subjecting them to temperatures above that of normal use in the papermaking machine. Such elevated temperatures cause or impart a dimensional stability that will exist until the fabric is subjected to still higher temperatures.

Methods of heat treating have heretofore called for passing the fabric over a large heated roll of through an oven. These arrangements require substantial, special heat treating equipment, and the evolved heat is delivered to the equipment as well as the fabric, such that there is a considerable preheating and cooling period for the equipment in addition to the treating of the fabric itself. As a result, the heating equipment is of a single purpose nature that cannot be readily used in other manufacturing processes, and such equipment cannot readily be removed from the work area, so that consequently it ties up plant space for the special task of heat setting synmay be quickly dismantled and removed from the finishing table when it is no longer required and lengthy periods for cooling the heat treating apparatus are not required, so that there is a consequent saving in time between heat treating and subsequent processing of a fabric.

An important aspect of the invention is the objective of satisfactorily heat treating a fabric that shrinks as treatment takes place. The fabric, which is in the form of an endless belt, is stretched between a pair of rolls to its desired lengthwise dimension, and then as heat is applied it shrinks in the crosswise direction. For open mesh fabrics this crosswise shrinkage may be as great as 20%, and this may cause severe wrinkling if unchecked, and the finished fabric will then be unsatisfactory. Further, if wrinkling is permitted to take place the resulting undulations will change the spacing between the fabric and the heat source, to which it is being subjected for the purpose of dimensional stabilization, resulting in an uneven application of heat and an uneven treatment of the fabric.

In the present invention smoothing rolls are placed across the fabric adjacent a radiant heat source, to thereby eliminate wrinkling. The rolls are relatively small and are positioned where crosswise dimensional change is taking place. Preferably, the rolls are at the very margin of the area of heat application, so that they border the heated area to not only function as an anti-wrinkle measure, but so as to delineate the area of heat and provide a heat entrapment in the form of a heat sink, to confine such heat and provide a controlled processing within a defined area. In this manner temperatures may be better regulated, and it is therefore an object of the invention to combine a radiant heat source with smoothing rolls located adjacent the field of heat.

The combination of a radiant heat source and smoothing rolls as constructed in accordance with the invention also provides a mobile assembly that can be readily erected on an existing finishing table, and also readily taken down after heat treatment is completed, to have immediate use of the table for other purposes. Hence, a further object of the invention is to provide a heat treating apparatus that is portable, and which does not deliver heat to surrounding equipment on the finishing table.

A further object of the invention is to provide a smoothing roll arrangement in which the rolls are disposed between, but at a substantial distance from stretch rolls of a finishing table, so that the portion of the fabric being treated is a span of the fabric held in suspension above the finishing table. These smoothing rolls are disposed over and under the fabric to deflect the fabric from the run between the stretch rolls at the particular area where the heat is being applied, and in this manner the objective of the invention to retain the fabric in a smooth, unw'rinkled condition at the area of heat treatment is attained.

The foregoing and other objects and advantages of the invention will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration and not of limitation a specific embodiment of the invention. The scope of the invention is to be determined from interpretation of the claims appended hereto.

In the drawings:

FIG. 1 is a side view in elevation of a finishing table with apparatus of the invention mounted upon the table fortreatment of a cloth also supported by the table,

FIG. 2 is a side view in elevation of the apparatus of the invention depicted in FIG. 1,

FIG. 3 is a fragmentary view in elevation of the heating I unit which comprises a part of the apparatus of the invention,

FIG. 4 is a fragmentary view in elevation of one of the two reflector units which comprise a part of the apparatus of the invention, and

FIG. is a fragmentary plan view of one of the two reflector units.

Referring now to the drawings, there is shown in FIG. 1 a finishing table 1 that has a pair of spaced, parallel side rails 2 upon which is mounted at both ends a set of journal blocks 3 and 4. The journal blocks 3, at the right hand end as viewed in FIG. 1, are secured firmly in position upon the side rails 2, and the journal blocks 4 at the left hand end are also held firmly in position, so that a fabric 5 mounted upon the table 1 can be placed in tension and held at a desired length. For adjustment purposes, the journal blocks 4 are moved into desired position by means of screw shafts 6 working in a set of blocks 7 clamped upon the rails 2. The journal blocks 3 and 4 mount suitable stretch rolls 8 and 9 upon which is mounted the fabric 5 that is to be treated by apparatus of the invention, and as discussed hereinbefore the fabric 5 is of a synthetic material with an open mesh. The fabric 5 is seen to be an endless belt, so as to pass around both stretch rolls 8, 9, and by holding the rolls 8, 9 in position the fabric 5 is similarly held at its finished length while it is moved across the finishing table 1 by driving one or both of the rolls 8, 9.

The apparatus of the invention is shown in FIG. 1 as being mounted on the finishing table 1 in a position between the rolls 8, 9. It comprises a heating unit 10 and a pair of reflector units 11, all of which are mounted upon the side rails 2. This apparatus is shown in detail in FIG. 2, and the heating unit 10 will first be described by reference to FIG. 3 in conjunction with FIG. 2. The heating unit 10 is similar at both of its ends, so the description will refer to the particular end shown in FIGS. 2 and 3, it being understood that FIG. 3 shows one end of the heating unit 10 with the two reflector units 11 removed from the finishing table 1 so that the construction of the unit 10 may be better understood. It is contemplated that in actual operation of the apparatus all of the units 10, 11 will be in position on the finishing table 1.

A channel shaped upright stand 12 is secured to a hori zontal base 13 fitted upon the side rail 2, and a bracing web 14 on each side of the stand 12 strengthens the assembly. A clamp 15 mounted on the base 13 holds the stand 12 in position upon the rail 2. An upper smoothing roll 16 is mounted between the two stands 12, with each end of the smoothing roll 16 being journaled in a vertically adjustable bearing 17 that is mounted upon an adjustment screw 18. The adjustment screw 18 may be raised and lowered by the manipulation of a pair of threaded collars 19 and 19- through which the screw 18 extends. The collar 19 is carried above a bracket 20, that stands out from the central web of the channel shaped upright stand 12, and the collar 19' is below the bracket 20, whereby the smoothing roll can be adjusted in position and then held so that it bears downward against the fabric 5.

Extending between and mounted upon the upright stands 12 is a hood 21 of inverted U-shape with its lower edges 22 bracketing the smoothing roll 16. The hood 21 has a mounting lug 23 at each end which extends through the web of the channel shaped stand 12, and it may be raised or lowered at each end through engagement of its lug 23 with a threaded adjustment shaft 24. The shaft 24 is carried by and is rotatable with an adjustment collar 25 at the top of the upright stand 12. By turning the adjustment collar 25 the associated adjustment shaft 24 is turned, and since the adjustment shaft 24 is threadedly received by the associated mounting lug 23 the hood 21 is accordingly raised or lowered.

The hood 21 serves as a hot air duct, and as specifically shown in FIG. 3, it includes a series of exhaust duct ports 26 opening upward from the top of the hood 21. The

hood 21 also serves as a support for radiant heating units 27 that are hung along opposite sides of the roll 16 and flush with the bottom edges 22 of the hood 21. For this purpose, a number of overhanging brackets 28 are bolted along each side of the hood 21, and these overhanging brackets 28 support a set of four rotatable drum shafts 29 that extend across nearly the entire length of the unit 10. The drum shafts 29 carry a plurality of cords 30 which each have one end attached to a shaft 29 and is wrapped around the shaft 29, so that upon rotation of the shaft 29 the cord 30 is raised or lowered. Thus, the shafts 29 function as cord drums from which the cords 30 are paid out or drawn in. To control the rotational position of the shafts 29 there is provided a dog and ratchet 31 at the end of each shaft 29, and an adjustment knob 32 is also provided.

The radiant heating units 27 are suspended from the cords 30 in positions directly over the fabric 5, so as to deliver heat thereto. These heating units 27 extend transversely of the fabric 5 across its entire width, similarly as the smoothing roll 16, so that the entire fabric 5 will be heat treated as it is moved through the apparatus of the invention. By adjustment of the cords 30 the positions of the heating units 27 are set to deliver the proper amount of heat in a uniform pattern. For example, the units 27 can be positioned parallel to the oblique direction of the fabric 5 in its run between the roll 16 and the rolls 37. Also, the intensity at the fabric surface is controlled by the spacing between the units 27 and the fabric 5.

The heating units 27 are preferably of a radiant type, such as panel heaters which give a substantially uniform distribution of heat, although tubular heaters may also be employed if satisfactory uniformness in the heat pattern is achieved. The radiant energy of the heaters should be within a spectrum which is absorbed by the fabric 5, so as to develop suflicient heating in a short time span of heat application, and to raise the temperatures of the fabric 5 to the levels required for imparting dimensional stability which will be retained during intended usage of the fabric 5. It has been found that for treating open mesh nylon fabrics, and other synthetic fabrics, that the radiant energy should have a wave length within a range of two to thirty microns, which is in the infra-red spectrum for effective absorption of the radiant energy.

Some of the energy will pass through the open mesh fabric 5, and to redirect this energy back to the fabric reflector surfaces are provided, as will now be described. The reflector units 11, both of which are shown in side view in FIGS. 1 and 2, are also represented in FIGS. 4 and 5. The right hand one, as seen in FIGS. 1 and 2, is shown in FIG. 4 with its reflector in lowered position, and the left hand one is shown in FIG. 5 as viewed from the top and with its reflector raised in the operable position. Both reflector units 11 are formed of like parts, being duplicates of one another, and hence like reference numerals are applied to like parts of each, and the description now to be given relates to each of the units 11.

Each reflector unit 11 has an upright stand 33 at each side of the finishing table 1, and each stand 33 has a base 34 with a clamp 35 which holds the stand 33 in position on a side rail 2 of the finishing table 1. Each stand 33 is channel shaped, and near its upper end it includes a bearing 36 in which is journaled the shaft of a lower smoothing roll 37 that is positioned across the underside of the fabric 5. The two lower smoothing rolls 37 of the two refiector units 11 cooperate with the upper smoothing roll 16 of the heating unit 10 to maintain the fabric 5 smooth and in an unwrinkled condition in the short span of fabric extending between the two lower rolls 37. These lower rolls 37 engage the fabric 5 over only a minor part of their cylindrical surface, similarly as the upper smoothing roll '16, so that the engagement of the fabric 5 with the smoothing rolls 16 and 37 is small in area, but sufficient to maintain the fabric 5 smooth in the area being heat treated, even though it is subject to transverse forces as shrinkage takes place.

, Each reflector stand 33 'has a rectangular bracket 38 at its upper end through which extends a reflector support bar 39 extending transversely along the underside of the fabric in a position just to the inside of the adjacent lower smoothing roll 37. Attached to the reflector support bar 39 is a flat, preferably planar reflector 40 having a reflective upper surface, which in actual practice has comprised a thin aluminum covering. Such reflector surface functions to reflect radiant energy that passes through the open mesh of the fabric, as described above, so as to redirect the energy toward the fabric 5 to obtain an eflicient heat absorption by the fabric. The reflector surface extends under the fabric 5 for the entire width of the fabric, and when the two reflector units 11 are both in position, as shown in FIG. 2, one reflector forms a continuation of the other so that there is an effective reflector surface extending for the entire distance between the two lower smoothing rolls 37. Heat is thus trapped, as well as radiant energy being redirected, so as to have maximum efliciency in raising the temperature of the fabric 5 to thermally stabilize the fabric.

Each reflector 40 is reinforced and strengthened by a reflector brace 41 which also is of thin sheet material. The brace 41 extends from the turned outer edge 42 of the associated reflector 40 to the reflector support bar 39. Thus the reflector 40 is held in a braced cantilever relation to its support bar 39, and both the reflector 40 and the reflector brace 41 are spot welded, or tacked in other appropriate fashion, to the associated support bar 39 so as to rotate in unison therewith.

To hold the reflector 40 in horizontal, or elevated position, such as shown in FIG. 2, there is provided a bifurcated arm 43 at each end of the bar 39 which rotates in unison therewith, so that when the arm 43 is raised to the horizontal the reflector 40 will likewise be raised to the same position. At the outer end of the arm 43 there is pinned thereto with .a pivotal connection a stay 44. The stay 44 includes a turnbuckle 45, so that its length may be precisely controlled, and at the lower end of the stay 44 is a three position hook 46 adapted to engage with a pin shaped hook catch 47 extending outward from the center web of the reflector stand 33. Thus, by raising the upper end of the stay 44 and engaging the three position hook 46 with the catch 47 the reflector 40 will be held in working position. This working position can be accurately controlled by adjustment of both the hook 46 and the turnbuckle 45.

In summary, the apparatus constitutes an assembly that may be easily attached to and erected upon a finishing table for treatment of a fabric, and then dismantled and removed so that the finishing table may immediately be used for other processing of the fabric. Thus, the apparatus may be an accessory for existing finishing tables, whereby expensive, single purpose equipment requiring its own plant space is eliminated, and further, in the use of the apparatus there is no heating of large pieces of machinery, such as stretch rolls or other rolls forming a part of the table. Hence, as soon as the apparatus of the invention is removed the finishing table is usable for other purposes, and there is no lengthy down time for cooling of parts.

To facilitate installation and removal of the apparatus, the heating unit can be lifted over a fabric by grappling the bails 48, and each reflector unit 11 can be translated sidewardly if a fabric is on the finishing table. In some instances, Where desired, a series of apparatuses of the invention can be placed on a finishing table, so that the heating and shrinking of the fabric can be accomplished in stages. Alternatively, the fabric may be passed around the rolls 8, 9 several times to treat the fabric in a succession of stages.

It is important in heat treating a synthetic fabric to carefully control temperatures of the fabric to deliver suflicient heat uniformly over the entire surface without excessive temperature rise that might be injurious to the fabric, but at sufficiently high temperatures to obtain the necessary dimensional stability in the anticipated use of the fabric. Panel type heaters carefully adjusted in position are preferred, and the position of the smoothing rolls is coordinated with that of the heaters. The lower rolls are positioned at the margin of the area of radiation emitted from the heaters to smooth the fabric in the specific vicinity of the fabric where transverse shrinkage is occurring, and to act as a heat sink for confining the area of heating. Thus, the apparatus heats a specific minor area of a relatively long span of fabric suspended between a pair of stretch rolls, whereby heat is confined to the specific apparatus of the invention.

We claim:

1. In a heat treating apparatus for an open mesh synthetic fabric suspended on a table having spaced side rails and stretch rolls for the fabric, the combination comprising:

a pair of stands each detachably mountable upon one of said side rails and rising upwardly from said rails when mounted thereon to an elevation above a fabric on the table; I

a first smoothing roll journaled in said pair of stands that extends across said table and over a fabric when said stands are mounted upon said rails, said roll being engageable with a fabric for smoothing the same;

a pair of radiant heat lamps supported between said pair of stands, one on each side of said first smoothing roll, which direct heat downwardly to a fabric passing beneath said roll;

said pair of stands, first smoothing roll and heat lamps being removable in an upward direction as a unit from the table and a fabric on the table;

.a second group of stands detachably mountable upon said rails which are in pairs with the stands of a pair being on opposite sides of the table;

a lower smoothing roll journaled in and extending between each pair of said second group of stands which is beneath and engageable with the underside of a fabric when the stands are mounted upon said rails for smoothing the same;

a heat reflector supported on each pair of said second group of stands, each reflector being positionable beneath one of said radiant heat lamps and beneath a fabric to reflect heat back to the fabric; and

said second group of stands being positionable on said rails to have said lower smoothing rolls located beneath the margin of the area of radiation of said radiant heat lamps.

2. In a heat treating apparatus for an open mesh synthetic fabric suspended on a table having spaced side rails and stretch rolls for the fabric, the combination comprising:

a pair of stands each detachably mountable upon one of said side rails and rising upwardly from said rails when mounted thereon to an elevation above a fabric on the table;

a first smoothing roll journaled in said pair of stands that extends across said table and over a fabric when said stands are mounted upon said rails, said roll being engageable with a fabric for smoothing the same;

radiant heat lamp means supported between said stands which direct heat downwardly to a fabric passing beneath said roll;

a second pair of stands detachably mountable upon said rails which are on the opposite sides of the table;

a lower smoothing roll journaled in and extending between said second pair of stands which is beneath and engageable with the underside of a fabric when the stands are mounted upon said rails for smoothing the same; and

7 8 a reflector supported on said second pair of stands that 2,651,702 9/1953 Burke et a1 34-87 is positionable beneath a fabric and said radiant heat 3,150,864 9/ 1964 Fetner et al. 263-3 lamp means to reflect heat back to the fabric. 3,221,416 12/ 1965 Smith 34-41 3,235,931 2/1966 Bruckner 26-l References Cited 5 3,281,952 11/1966 Mullaney 34-41 UNITED STATES PATENTS 1,571,282 2/1926 Leculier 34 41 X FREDERICK L. MATTESON, JR., Primal y Exammer. 1,802,407 4/1931 Danninger et a1. 34 41 X C. R. REMKE, H. B. RAMEY, Assistant Examiners.

2,591,861 1 4/1952 Pannaci 281 

2. IN A HEAT TREATING APPARATUS FOR AN OPEN MESH SYNTHETIC FABRIC SUSPENDED ON A TABLE HAVING SPACED SIDE RAILS AND STRETCH ROLLS FOR THE FABRIC, THE COMBINATION COMPRISING: A PAIR OF STANDS EACH DETACHABLY MOUNTABLE UPON ONE OF SAID SIDE RAILS AND RISING UPWARDLY FROM SAID RAILS WHEN MOUNTED THEREON TO AN ELEVATION ABOVE A FABRIC ON THE TABLE; A FIRST SMOOTHING ROLL JOURNALED IN SAID PAIR OF STANDS THAT EXTENDS ACROSS SAID TABLE AND OVER A FABRIC WHEN SAID STANDS ARE MOUNTED UPON SAID RAILS, SAID ROLL BEING ENGAGEABLE WITH A FABRIC FOR SMOOTHING THE SAME; RADIANT HEAT LAMP MEANS SUPPORTED BETWEEN SAID STANDS WHICH DIRECT HEAT DOWNWARDLY TO A FABRIC PASSING BENEATH SAID ROLL; A SECOND PAIR OF STANDS DETACHABLY MOUNTABLE UPON SAID RAILS WHICH ARE ON THE OPPOSITE SIDES OF THE TABLE; A LOWER SMOOTHING ROLL JOURNALED IN AND EXTENDING BETWEEN SAID SECOND PAIR OF STANDS WHICH IS BENEATH 